Fix null dereference on MemoryCache.

third_party/WebKit/Source/core/css/CSSCrossfadeValue.h

Index: third_party/WebKit/Source/core/css/CSSCrossfadeValue.h
diff --git a/third_party/WebKit/Source/core/css/CSSCrossfadeValue.h b/third_party/WebKit/Source/core/css/CSSCrossfadeValue.h
index 719803907cf591a63eedc74c253e200a567dba65..75845a51094d40792a7774bf53415d931738da2c 100644
--- a/third_party/WebKit/Source/core/css/CSSCrossfadeValue.h
+++ b/third_party/WebKit/Source/core/css/CSSCrossfadeValue.h
@@ -26,6 +26,7 @@
 #ifndef CSSCrossfadeValue_h
 #define CSSCrossfadeValue_h
 
+#include "core/CoreExport.h"
 #include "core/css/CSSImageGeneratorValue.h"
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/fetch/ImageResource.h"
@@ -39,7 +40,7 @@ class ImageResource;
 class CrossfadeSubimageObserverProxy;
 class LayoutObject;
 
-class CSSCrossfadeValue final : public CSSImageGeneratorValue {
+class CORE_EXPORT CSSCrossfadeValue final : public CSSImageGeneratorValue {
     friend class CrossfadeSubimageObserverProxy;
 public:
     static PassRefPtrWillBeRawPtr<CSSCrossfadeValue> create(PassRefPtrWillBeRawPtr<CSSValue> fromValue, PassRefPtrWillBeRawPtr<CSSValue> toValue, PassRefPtrWillBeRawPtr<CSSPrimitiveValue> percentageValue)